I bought a nice rig from my buddy. I always had my eye on it anyway, so I finally talked him into it.

I was recently reading that the problem with this rig (and similar Icom rigs of this era...) is the e-prom logic board powered by a lithium battery.

I'm not sure how long Mike had this rig. But I am surely concerned about the possibility of the lithium battery going bad. I'm all set with instructions on how to solder in a temp 3 volt source while replacing the battery.

HOWEVER, this rig was sent in to Icom for a "tune-up" after Mike bought it. I asked Mike if he had any documents....or....if he could remember if Icom modified this lithium battery board, as they were doing with most of these style rigs. Mike told me he just didn't know.

My questions: How can I tell if the mod was made? Will the lithium battery now be missing from the circuitry after the new mode?

Another question, does this lithium battery give ANY indication that it might be on the brink of dying? Or does it just suddenly crap out and all of your data is lost forever?

I'm just a tad concerned. Although Mike had the rig for about ten years, and had the "tune-up' shortly after HE bought it, he didn't operate the rig hardly at all. In fact, I'm the one giving it it's first real work-out. I've owned it since the first of March.

Those lithium 'coin cells' are supposed to last 8 to 10 years, so I would think its time to 'get it done' now. To check if the mod was done, open up the rig--I believe the battery is either behind the bottom panel of the rig or behind the front panel. If the mod wasn't done, then the battery will still be buried, and the rig will have to come apart to find out if it needs replacement.

Unfortunately, the battery will not give any sign its going to fail--it just will. If you can locate the battery, putting a meter on it will probably give you a clue--if its lower than 2.5 volts--replace it.

I replaced the OEM board in one I had with one from IK2RND, because I was going to sell the radio.

If the cell fails, eprom memory is lost and will need Icom's help. If in doubt, it might be a good idea to replace the battery (or the board) you can replace the battery by keeping the board powered by a 2nd source during the process. A google search reselts in the instructions to do so. Battery change is very little effort - But if you loose power, you just lost the eprom programming.

The newer BR2325 may have a blue plastic rim, the ones I bought from Mouser did.

You can check the condition of the battery easily with a voltmeter. If you have a reading of 3V DC then you don't really have to change anything if the radio is working.

Use ESD (anti static) precautions - at least a grounded wrist strap when handling the board with it removed from the case and when soldering or making measurements. Be careful not to bend any of the pins which hold the board in place. A magnifying glass helps when soldering, getting solder splashes or traces on the PCB must be avoided, as it can be just as lethal to the RAM as losing power.

I just purchased a used IC-745 for a very cheap price and it is supposedly dead. It will not power up at all. I have not received the radio yet to confirm but can this be a symtom of a bad eprom battery failure as well? I fear that it may be more than this but without experience in this radio I'm not sure what to expect.

I just purchased a used IC-745 for a very cheap price and it is supposedly dead. It will not power up at all. I have not received the radio yet to confirm but can this be a symtom of a bad eprom battery failure as well? I fear that it may be more than this but without experience in this radio I'm not sure what to expect.

I answered this more fully on the thread you started.

Now, thinking about that Lithium battery problem, of course there is the chance that is what is the problem with your radio, but until you get it into your hands, it still could be any other thing as well, such as power supply prob or broken internal connection, etc.

If in question, replace it. Then you will know it's condition! It is not an expensive part. Just work, that's all!73s.

-Mike.

Not with this particular model.

If the battery is dead, the radio is bricked.

If the battery is still good and you would like to replace it before that happens, you have to first parallel a second battery to preserve the radio's memory of what it is before siply disconnecting the original cell, or you will indeed brick the radio.

Once bricked, the radio *must* go back to ICOM repair to be reprogrammed.

As I said before, the memory can be reprogrammed by ICOM. This requires only the memory board and not the radio to be returned. However the improved board with the non volatile memory is less expensive than the reprogramming.

A couple of weeks ago, I dug my old 745 out of the closet and decided to get back on HF. The radio was brain-dead, plus I remembered that the preamp switch was flaky. I called Icom parts to ask about the switch and was told that the 745 was no longer supported, no parts were stocked, and they didn't know of a source for the preamp switch. I then asked about the "reprogramming" of the RAM board, and was told that Icom no longer provided that service. So much for long-term customer support. I contacted IK2RND and he still has the EPROM boards for the Icom radios, so I ordered one for the 745. Regarding the preamp switch, I VERY CAREFULLY disassembled the switch and cleaned the internal contacts with Electrosolve contact cleaner and reassembled the switch. It now works every time. If you decide to clean one of these switches, be careful not to lose any of the tiny parts inside!

Just for clarification purposes, the reason that Icom used the lithium batteries was due to the fact that dynamic RAM chips were far cheaper than large EPROMs back in the late Seventies/early Eighties when these radios (745, 751, 551, 251) were designed. They dumped the firmware to a dynamic RAM and used a lithium battery to hold the memory. Obviously, they didn't expect a long product life cycle for these radios. The "reprogramming" service was likely an afterthought intended to keep customers happy once the batteries started going belly-up in the early-mid Nineties.

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